The present invention relates to a liquid dispenser.
A large number of dispensers already exist that are of the type comprising a reservoir provided at its top with an outflow orifice which is closed off by an inlet valve and which opens out into a metering chamber of variable volume, which chamber communicates, via an outlet valve, with a discharge duct provided in a dispensing head.
Unfortunately, in such dispensers, the variations in the volume of the metering chamber and the compression of the liquid contained in the chamber that is necessary for said liquid to be discharged are obtained by means of a piston working axially in said chamber. The piston generally co-operates with resilient return means in the form of one or more metal helical springs.
Furthermore, the respective structures of each of the valves are, in particular, distinct because the inlet valve works without being stressed, unlike the outlet valve which is subjected to the high pressures prevailing in the chamber, and which thus operates in the manner of a pressure-relief valve.
In addition, in a very widespread and simple version, the inlet valve includes a metal ball in contact with the liquid.
As a result, conventional dispensers are composite because they have both metal parts and plastics parts, which poses manufacturing, assembly, and recycling problems, and can risk degrading the qualities of the liquid.
More precisely, the invention relates to a dispenser comprising a reservoir provided at its top with an outflow orifice which is situated at the end of a cylindrical rim, which is closed off by an inlet valve, and which opens out into a metering chamber of variable volume, which chamber is defined by the wall of a bellows that is elastically deformable at least in part, and communicates, via an outlet valve received in a bush extending said chamber, with a discharge duct provided in a dispensing head, the moving elements of the inlet valve and of the outlet valve being identical.
Document WO 97/42124 discloses a dispenser of that type, in which the moving elements of the inlet and outlet valves move in translation so as to dispense the substance contained in the reservoir, their strokes being limited by abutments. The mounting of the inlet valve and of the outlet valve therefore does not take account of the fact that the two valves are subjected to different stresses during operation of the dispenser.
The present invention seeks to improve that prior art by using a single component material that is easy to recycle.
The object is achieved as a result of the fact that the height of the rim which receives the inlet valve is less than the height of the bush which receives the outlet valve so that the moving element of the outlet valve is fitted under stress, whereas the moving element of the inlet valve has a small amount of freedom of movement in translation.
In a specific embodiment, each of said valves has an elastically deformable frustoconical closure cap extended by snap-fastening catches defining channels between them for passing the liquid.
In another variant, said reservoir is equipped with a collar whose sidewall guides the dispensing head and whose top edge retains said head.
Preferably, the bellows is fixed to the top portion of the reservoir.
According to other characteristics, said bellows is provided with a top shoulder against which stiffener fins carried by said head bear.
The dispenser of the invention has a structure that is very simple and ergonomic, and that is constituted of a small number of parts. In addition, it offers the industrial and economic advantage of being suitable for being made by molding (injection or compression molding) by using a single common plastics material for all of the component parts, which, in addition, makes it possible to preserve the qualities of the liquid.